Artificial muscles comprising an electrode pair and a clamping device for compressing the electrode pair

ABSTRACT

An artificial muscle includes a housing including an electrode region and an expandable fluid region; an electrode pair positioned in the electrode region of the housing, the electrode pair comprising a first electrode positioned adjacent a first surface of the housing and a second electrode positioned adjacent a second surface of the housing, the first electrode and the second electrode each having a first end proximate the expandable fluid region and a second end opposite the expandable fluid region; a dielectric fluid housed within the housing; and a clamping device applying a force against the first electrode and the second electrode at the second end of the first electrode and the second electrode, wherein the electrode pair is actuatable between a non-actuated state and an actuated state such that actuation from the non-actuated state to the actuated state directs the dielectric fluid into the expandable fluid region.

TECHNICAL FIELD

The present specification generally relates to apparatus and methods forfocused inflation on at least one surface of a device, and, morespecifically, apparatus and methods for utilizing an electrode pair todirect a fluid to inflate the device.

BACKGROUND

Current robotic technologies rely on rigid components, such asservomotors to perform tasks, often in a structured environment. Thisrigidity presents limitations in many robotic applications, caused, atleast in part, by the weight-to-power ratio of servomotors and otherrigid robotics devices. The field of soft robotics improves on theselimitations by using artificial muscles and other soft actuators.Artificial muscles attempt to mimic the versatility, performance, andreliability of a biological muscle. Some artificial muscles rely onfluidic actuators, but fluidic actuators require a supply of pressurizedgas or liquid, and fluid transport must occur through systems ofchannels and tubes, limiting the speed and efficiency of the artificialmuscles. Other artificial muscles use thermally activated polymerfibers, but these are difficult to control and operate at lowefficiencies. Additionally, any space or gap formed between an electrodepair of the artificial muscles may result in an increased voltagerequired to close the gap and thus actuate the artificial muscles.

Accordingly, a need exists for improved artificial muscles withincreased actuator power per unit volume by reducing the existence ofany gaps between an electrode pair of the artificial muscles.

SUMMARY

In one embodiment, an artificial muscle includes: a housing including anelectrode region and an expandable fluid region; an electrode pairpositioned in the electrode region of the housing, the electrode pairincluding a first electrode positioned adjacent a first surface of thehousing and a second electrode positioned adjacent a second surface ofthe housing, the first electrode and the second electrode each having afirst end proximate the expandable fluid region and a second endopposite the expandable fluid region; a dielectric fluid housed withinthe housing; and a clamping device applying a force against the firstelectrode and the second electrode at the second end of the firstelectrode and the second electrode, wherein the electrode pair isactuatable between a non-actuated state and an actuated state such thatactuation from the non-actuated state to the actuated state directs thedielectric fluid into the expandable fluid region.

In another embodiment, an artificial muscle includes: a housingincluding an electrode region and an expandable fluid region; anelectrode pair positioned in the electrode region of the housing, theelectrode pair including a first electrode fixed to a first surface ofthe housing and a second electrode fixed to a second surface of thehousing, at least one of the first electrode and the second electrodeincluding a central opening encircling the expandable fluid region, thefirst electrode and the second electrode each having a first endproximate the expandable fluid region and a second end opposite theexpandable fluid region; a dielectric fluid housed within the housing;and a clamping device applying a force against the first electrode andthe second electrode at the second end of the first electrode and thesecond electrode to reduce a gap between the second end of the firstelectrode and the second end of the second electrode, wherein theelectrode pair is actuatable between a non-actuated state and anactuated state such that actuation from the non-actuated state to theactuated state directs the dielectric fluid into the expandable fluidregion.

In yet another embodiment, a method for actuating an artificial muscleassembly includes generating a voltage using a power supply electricallycoupled to an electrode pair of an artificial muscle, the artificialmuscle including: a housing with an electrode region and an expandablefluid region, the electrode pair is positioned in the electrode regionof the housing, the electrode pair including a first electrodepositioned adjacent a first surface of the housing and a secondelectrode positioned adjacent a second surface of the housing, the firstelectrode and the second electrode each having a first end proximate theexpandable fluid region and a second end opposite the expandable fluidregion; a clamping device applying a force against the first electrodeand the second electrode at the second end of the first electrode andthe second electrode; and a dielectric fluid housed within the housing,and applying the voltage to the electrode pair of the artificial muscle,thereby actuating the electrode pair from a non-actuated state and anactuated state such that the dielectric fluid is directed into theexpandable fluid region of the housing and expands the expandable fluidregion.

These and additional features provided by the embodiments describedherein will be more fully understood in view of the following detaileddescription, in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments set forth in the drawings are illustrative and exemplaryin nature and not intended to limit the subject matter defined by theclaims. The following detailed description of the illustrativeembodiments can be understood when read in conjunction with thefollowing drawings, where like structure is indicated with likereference numerals and in which:

FIG. 1 schematically depicts an exploded view of an example artificialmuscle, according to one or more embodiments shown and described herein;

FIG. 2 schematically depicts a top view of the artificial muscle of FIG.1 , according to one or more embodiments shown and described herein;

FIG. 3 schematically depicts a top view of another example artificialmuscle, according to one or more embodiments shown and described herein;

FIG. 4 schematically depicts a cross-sectional view of the artificialmuscle of FIG. 1 taken along line 4-4 in FIG. 2 in a non-actuated stateand including a plurality of clamping devices, according to one or moreembodiments shown and described herein;

FIG. 5 schematically depicts a cross-sectional view of the artificialmuscle of FIG. 4 in an actuated state, according to one or moreembodiments shown and described herein;

FIG. 6 schematically depicts a cross-sectional view of another exampleartificial muscle in a non-actuated state, according to one or moreembodiments shown and described herein;

FIG. 7 schematically depicts a cross-sectional view of the artificialmuscle of FIG. 6 in an actuated state, according to one or moreembodiments shown and described herein;

FIG. 8 schematically depicts a perspective view of the clamping deviceof the artificial muscle of FIG. 4 , according to one or moreembodiments shown and described herein;

FIG. 9 schematically depicts a partial perspective view of an embodimentof a clamping device, according to one or more embodiments shown anddescribed herein;

FIG. 10 schematically depicts a perspective view of an embodiment of aclamping device, according to one or more embodiments shown anddescribed herein;

FIG. 11 schematically depicts an artificial muscle assembly including aplurality of the artificial muscles of FIG. 1 and a plurality of theclamping devices of FIG. 10 , according to one or more embodiments shownand described herein; and

FIG. 12 schematically depicts an actuation system for operating theartificial muscle of FIG. 1 , according to one or more embodiments shownand described herein.

DETAILED DESCRIPTION

Embodiments described herein are directed to artificial muscles andartificial muscle assemblies. The artificial muscles described hereinare actuatable to selectively raise and lower a region of the artificialmuscles to provide a selective, on demand inflated expandable fluidregion. The artificial muscles include a housing and an electrode pair.A dielectric fluid is housed within the housing, and the housingincludes an electrode region and an expandable fluid region, where theelectrode pair is positioned in the electrode region. The electrode pairincludes a first electrode, which may be fixed to a first surface of thehousing and a second electrode, which may be fixed to a second surfaceof the housing. The electrode pair is actuatable between a non-actuatedstate and an actuated state such that actuation from the non-actuatedstate to the actuated state directs the dielectric fluid into theexpandable fluid region. This expands the expandable fluid region,raising a portion of the artificial muscle on demand. Further,artificial muscles include one or more clamping devices configured toapply a force against the first electrode and the second electrode toreduce a gap or space therebetween. Due to the reduced gap between adistal end of the first electrode and the second electrode opposite theexpandable fluid region, a reduced voltage is required to actuate theartificial muscles. Various embodiments of the artificial muscles andthe operation of the artificial muscles are described in more detailherein. Whenever possible, the same reference numerals will be usedthroughout the drawings to refer to the same or like parts.

Referring now to FIGS. 1 and 2 , an artificial muscle 100 is shown. Theartificial muscle 100 includes a housing 102, an electrode pair 104,including a first electrode 106 and a second electrode 108, fixed toopposite surfaces of the housing 102, a first electrical insulator layer110 fixed to the first electrode 106, and a second electrical insulatorlayer 112 fixed to the second electrode 108. In some embodiments, thehousing 102 is a one-piece monolithic layer including a pair of oppositeinner surfaces, such as a first inner surface 114 and a second innersurface 116, and a pair of opposite outer surfaces, such as a firstouter surface 118 and a second outer surface 120. In some embodiments,the first inner surface 114 and the second inner surface 116 of thehousing 102 are heat-sealable. In other embodiments, the housing 102 maybe a pair of individually fabricated film layers, such as a first filmlayer 122 and a second film layer 124. Thus, the first film layer 122includes the first inner surface 114 and the first outer surface 118,and the second film layer 124 includes the second inner surface 116 andthe second outer surface 120.

Throughout the ensuing description, reference may be made to the housing102 including the first film layer 122 and the second film layer 124, asopposed to the one-piece housing. It should be understood that eitherarrangement is contemplated. In some embodiments, the first film layer122 and the second film layer 124 generally include the same structureand composition. For example, in some embodiments, the first film layer122 and the second film layer 124 each comprises biaxially orientedpolypropylene (BOPP).

The first electrode 106 and the second electrode 108 are each positionedbetween the first film layer 122 and the second film layer 124. In someembodiments, the first electrode 106 and the second electrode 108 areeach aluminum-coated polyester such as, for example, Mylar®. Inaddition, one of the first electrode 106 and the second electrode 108 isa negatively charged electrode and the other of the first electrode 106and the second electrode 108 is a positively charged electrode. Forpurposes discussed herein, either electrode 106, 108 may be positivelycharged so long as the other electrode 106, 108 of the artificial muscle100 is negatively charged.

The first electrode 106 has a film-facing surface 126 and an oppositeinner surface 128. The first electrode 106 is positioned against thefirst film layer 122, specifically, the first inner surface 114 of thefirst film layer 122. In addition, the first electrode 106 includes afirst terminal 130 extending from the first electrode 106 past an edgeof the first film layer 122 such that the first terminal 130 can beconnected to a power supply to actuate the first electrode 106.Specifically, the first terminal 130 is coupled, either directly or inseries, to a power supply and a controller of an actuation system 400,as shown in FIG. 12 . Similarly, the second electrode 108 has afilm-facing surface 148 and an opposite inner surface 150. The secondelectrode 108 is positioned against the second film layer 124,specifically, the second inner surface 116 of the second film layer 124.The second electrode 108 includes a second terminal 152 extending fromthe second electrode 108 past an edge of the second film layer 124 suchthat the second terminal 152 can be connected to a power supply and acontroller of the actuation system 400 to actuate the second electrode108.

With respect now to the first electrode 106, the first electrode 106includes two or more fan portions 132 extending radially from a centeraxis C of the artificial muscle 100. In some embodiments, the firstelectrode 106 includes only two fan portions 132 positioned on oppositesides or ends of the first electrode 106. In some embodiments, the firstelectrode 106 includes more than two fan portions 132, such as three,four, or five fan portions 132. In embodiments in which the firstelectrode 106 includes an even number of fan portions 132, the fanportions 132 may be arranged in two or more pairs of fan portions 132.As shown in FIG. 1 , the first electrode 106 includes four fan portions132. In this embodiment, the four fan portions 132 are arranged in twopairs of fan portions 132, where the two individual fan portions 132 ofeach pair are diametrically opposed to one another.

Each fan portion 132 has a first side edge 132 a and an opposite secondside edge 132 b. Each fan portion 132 also has a first end 134 and anopposite second end 136 extending between the first side edge 132 a andthe second side edge 132 b. As shown, the first terminal 130 extendsfrom the second end 136 of one of the fan portions 132 and is integrallyformed therewith. A channel 133 is at least partially defined byopposing side edges 132 a, 132 b of adjacent fan portions 132 and, thus,extends radially toward the center axis C. The channel 133 terminates atan end 140 a of a bridge portion 140 interconnecting adjacent fanportions 132.

As shown in FIG. 1 , dividing lines D are included to depict theboundary between the fan portions 132 and the bridge portions 140. Thedividing lines D extend from the side edges 132 a, 132 b of the fanportions 132 to the first end 134 of the fan portions 132 collinear withthe side edges 132 a, 132 b. It should be understood that dividing linesD are shown in FIG. 1 for clarity and that the fan portions 132 areintegral with the bridge portions 140. The first end 134 of the fanportion 132, which extends between adjacent bridge portions 140, definesan inner length of the fan portion 132. Due to the geometry of the fanportion 132 tapering toward the center axis C between the first sideedge 132 a and the second side edge 132 b, the second end 136 of the fanportion 132 defines an outer length of the fan portion 132 that isgreater than the inner length of the fan portion 132.

Moreover, each fan portion 132 has a pair of corners 132 c defined by anintersection of the second end 136 and each of the first side edge 132 aand the second side edge 132 b of the fan portion 132. In embodiments,the corners 132 c are formed at an angle equal to or less than 90degrees. In other embodiments, the corners 132 c are formed at an acuteangle.

As shown in FIG. 1 , each fan portion 132 has a first side lengthdefined by a distance between the first end 134 of the fan portion 132and the second end 136 of the fan portion 132 along the first side edge132 a and the dividing line D that is collinear with the first side edge132 a. Each fan portion 132 also has a second side length defined by adistance between the first end 134 of the fan portion 132 and the secondend 136 of the fan portion 132 along the second side edge 132 b and thedividing line D that is collinear with the second side edge 132 b. Inembodiments, the first side length is greater than the second sidelength of the fan portion 132 such that the first electrode 106 has anellipsoid geometry.

The second end 136, the first side edge 132 a and the second side edge132 b of each fan portion 132, and the bridge portions 140interconnecting the fan portions 132 define an outer perimeter 138 ofthe first electrode 106. In embodiments, a central opening 146 is formedwithin the first electrode 106 between the fan portions 132 and thebridge portions 140, and is coaxial with the center axis C. Each fanportion 132 has a fan length extending from a perimeter 142 of thecentral opening 146 to the second end 136 of the fan portion 132. Eachbridge portion 140 has a bridge length extending from a perimeter 142 ofthe central opening 146 to the end 140 a of the bridge portion 140,i.e., the channel 133. As shown, the bridge length of each of the bridgeportions 140 is substantially equal to one another. Each channel 133 hasa channel length defined by a distance between the end 140 a of thebridge portion 140 and the second end 136 of the fan portion 132. Due tothe bridge length of each of the bridge portions 140 being substantiallyequal to one another and the first side length of the fan portions 132being greater than the second side length of the fan portions 132, afirst pair of opposite channels 133 has a channel length greater than achannel length of a second pair of opposite channels 133. As shown, awidth of the channel 133 extending between opposing side edges 132 a,132 b of adjacent fan portions 132 remains substantially constant due toopposing side edges 132 a, 132 b being substantially parallel to oneanother.

In embodiments, the central opening 146 has a radius of 2 centimeters(cm) to 5 cm. In embodiments, the central opening 146 has a radius of 3cm to 4 cm. In embodiments, a total fan area of each of the fan portions132 is equal to or greater than twice an area of the central opening146. It should be appreciated that the ratio between the total fan areaof the fan portions 132 and the area of the central opening 146 isdirectly related to a total amount of deflection of the first film layer122 when the artificial muscle 100 is actuated, as discussed herein. Inembodiments, the bridge length is 20% to 50% of the fan length. Inembodiments, the bridge length is 30% to 40% of the fan length. Inembodiments in which the first electrode 106 does not include thecentral opening 146, the fan length and the bridge length may bemeasured from a perimeter of an imaginary circle coaxial with the centeraxis C.

Similar to the first electrode 106, the second electrode 108 includestwo or more fan portions 154 extending radially from the center axis Cof the artificial muscle 100. The second electrode 108 includessubstantially the same structure as the first electrode 106 and, thus,includes the same number of fan portions 154. Specifically, the secondelectrode 108 is illustrated as including four fan portions 154.However, it should be appreciated that the second electrode 108 mayinclude any suitable number of fan portions 154.

Each fan portion 154 of the second electrode 108 has a first side edge154 a and an opposite second side edge 154 b. Each fan portion 154 alsohas a first end 156 and an opposite second end 158 extending between thefirst side edge 154 a and the second side edge 154 b. As shown, thesecond terminal 152 extends from the second end 158 of one of the fanportions 154 and is integrally formed therewith. A channel 155 is atleast partially defined by opposing side edges 154 a, 154 b of adjacentfan portions 154 and, thus, extends radially toward the center axis C.The channel 155 terminates at an end 162 a of a bridge portion 162interconnecting adjacent fan portions 154.

As shown in FIG. 1 , additional dividing lines D are included to depictthe boundary between the fan portions 154 and the bridge portions 162.The dividing lines D extend from the side edges 154 a, 154 b of the fanportions 154 to the first end 156 of the fan portions 154 collinear withthe side edges 154 a, 154 b. It should be understood that dividing linesD are shown in FIG. 1 for clarity and that the fan portions 154 areintegral with the bridge portions 162. The first end 156 of the fanportion 154, which extends between adjacent bridge portions 162, definesan inner length of the fan portion 154. Due to the geometry of the fanportion 154 tapering toward the center axis C between the first sideedge 154 a and the second side edge 154 b, the second end 158 of the fanportion 154 defines an outer length of the fan portion 154 that isgreater than the inner length of the fan portion 154.

Moreover, each fan portion 154 has a pair of corners 154 c defined by anintersection of the second end 158 and each of the first side edge 154 aand the second side edge 154 b of the fan portion 154. In embodiments,the corners 154 c are formed at an angle equal to or less than 90degrees. In other embodiments, the corners 154 c are formed at an acuteangle. As described in more detail herein, during actuation of theartificial muscle 100, the corners 132 c of the first electrode 106 andthe corners 154 c of the second electrode 108 are configured to beattracted to one another at a lower voltage as compared to the rest ofthe first electrode 106 and the second electrode 108. Thus, actuation ofthe artificial muscle 100 initially at the corners 132 c, 154 c resultsin the outer perimeter 138 of the first electrode 106 and the outerperimeter 160 of the second electrode 108 being attracted to one anotherat a lower voltage and reducing the likelihood of air pockets or voidsforming between the first electrode 106 and the second electrode 108after actuation of the artificial muscle 100.

As shown in FIGS. 1 and 2 , in embodiments, the first side edge 154 a ofeach fan portion 154 has a first side length defined by a distancebetween the first end 156 of the fan portion 154 and the second end 158of the fan portion 154 along the first side edge 154 a and the dividingline D that is collinear with the first side edge 154 a. Each fanportion 154 also has a second side length defined by a distance betweenthe first end 156 of the fan portion 154 and the second end 158 of thefan portion 154 along the second side edge 154 b and the dividing line Dthat is collinear with the second side edge 154 b. In embodiments, thefirst side length is greater than the second side length of the fanportion 154 such that the second electrode 108 has an ellipsoid geometrycorresponding to the geometry of the first electrode 106.

The second end 158, the first side edge 154 a and the second side edge154 b of each fan portion 154, and the bridge portions 162interconnecting the fan portions 154 define an outer perimeter 160 ofthe second electrode 108. In embodiments, a central opening 168 isformed within the second electrode 108 between the fan portions 154 andthe bridge portions 162, and is coaxial with the center axis C. Each fanportion 154 has a fan length extending from a perimeter 164 of thecentral opening 168 to the second end 158 of the fan portion 154. Eachbridge portion 162 has a bridge length extending from the centralopening 168 to the end 162 a of the bridge portion 162, i.e., thechannel 155. As shown, the bridge length of each of the bridge portions162 is substantially equal to one another. Each channel 155 has achannel length defined by a distance between the end 162 a of the bridgeportion 162 and the second end 158 of the fan portion 154. Due to thebridge length of each of the bridge portions 162 being substantiallyequal to one another and the first side length of the fan portions 154being greater than the second side length of the fan portions 154, afirst pair of opposite channels 155 has a channel length greater than achannel length of a second pair of opposite channels 155. As shown, awidth of the channel 155 extending between opposing side edges 154 a,154 b of adjacent fan portions 154 remains substantially constant due toopposing side edges 154 a, 154 b being substantially parallel to oneanother.

In embodiments, the central opening 168 has a radius of 2 cm to 5 cm. Inembodiments, the central opening 168 has a radius of 3 cm to 4 cm. Inembodiments, a total fan area of each of the fan portions 154 is equalto or greater than twice an area of the central opening 168. It shouldbe appreciated that the ratio between the total fan area of the fanportions 154 and the area of the central opening 168 is directly relatedto a total amount of deflection of the second film layer 124 when theartificial muscle 100 is actuated. In embodiments, the bridge length is20% to 50% of the fan length. In embodiments, the bridge length is 30%to 40% of the fan length. In embodiments in which the second electrode108 does not include the central opening 168, the fan length and thebridge length may be measured from a perimeter of an imaginary circlecoaxial with the center axis C.

As described herein, the first electrode 106 and the second electrode108 each have a central opening 146, 168 coaxial with the center axis C.However, it should be understood that the first electrode 106 does notneed to include the central opening 146 when the central opening 168 isprovided within the second electrode 108, as shown in the embodimentillustrated in FIGS. 6 and 7 . Alternatively, the second electrode 108does not need to include the central opening 168 when the centralopening 146 is provided within the first electrode 106.

Referring again to FIG. 1 , the first electrical insulator layer 110 andthe second electrical insulator layer 112 have a substantially ellipsoidgeometry generally corresponding to the geometry of the first electrode106 and the second electrode 108, respectively. Thus, the firstelectrical insulator layer 110 and the second electrical insulator layer112 each have fan portions 170, 172 and bridge portions 174, 176corresponding to like portions on the first electrode 106 and the secondelectrode 108. Further, the first electrical insulator layer 110 and thesecond electrical insulator layer 112 each have an outer perimeter 178,180 corresponding to the outer perimeter 138 of the first electrode 106and the outer perimeter 160 of the second electrode 108, respectively,when positioned thereon.

It should be appreciated that, in some embodiments, the first electricalinsulator layer 110 and the second electrical insulator layer 112generally include the same structure and composition. As such, in someembodiments, the first electrical insulator layer 110 and the secondelectrical insulator layer 112 each include an adhesive surface 182, 184and an opposite non-sealable surface 186, 188, respectively. Thus, insome embodiments, the first electrical insulator layer 110 and thesecond electrical insulator layer 112 are each a polymer tape adhered tothe inner surface 128 of the first electrode 106 and the inner surface150 of the second electrode 108, respectively.

Referring now to FIGS. 2, 4, and 5 , the artificial muscle 100 is shownin its assembled form. As shown in FIG. 2 , the second electrode 108 isstacked on top of the first electrode 106 and, therefore, the firstelectrode 106, the first film layer 122, and the second film layer 124are not shown. In its assembled form, the first electrode 106, thesecond electrode 108, the first electrical insulator layer 110, and thesecond electrical insulator layer 112 are sandwiched between the firstfilm layer 122 and the second film layer 124. The first film layer 122is partially sealed to the second film layer 124 at an area surroundingthe outer perimeter 138 of the first electrode 106 and the outerperimeter 160 of the second electrode 108. In some embodiments, thefirst film layer 122 is heat-sealed to the second film layer 124.Specifically, in some embodiments, the first film layer 122 is sealed tothe second film layer 124 to define a sealed portion 190 surrounding thefirst electrode 106 and the second electrode 108. The first film layer122 and the second film layer 124 may be sealed in any suitable manner,such as using an adhesive, heat sealing, vacuum sealing, or the like.

The first electrode 106, the second electrode 108, the first electricalinsulator layer 110, and the second electrical insulator layer 112provide a barrier that prevents the first film layer 122 from sealing tothe second film layer 124, thereby forming an unsealed portion 192. Theunsealed portion 192 of the housing 102 includes an electrode region194, in which the electrode pair 104 is provided, and an expandablefluid region 196, which is surrounded by the electrode region 194. Thecentral openings 146, 168 of the first electrode 106 and the secondelectrode 108 define the expandable fluid region 196 and are arranged tobe axially stacked on one another. Although not shown, the housing 102may be cut to conform to the geometry of the electrode pair 104 andreduce the size of the artificial muscle 100, namely, the size of thesealed portion 190.

A dielectric fluid 198 is provided within the unsealed portion 192 andflows freely between the first electrode 106 and the second electrode108. A “dielectric” fluid as used herein is a medium or material thattransmits electrical force without conduction and as such has lowelectrical conductivity. Some non-limiting example dielectric fluidsinclude perfluoroalkanes, transformer oils, and deionized water. Itshould be appreciated that the dielectric fluid 198 may be injected intothe unsealed portion 192 of the artificial muscle 100 using a needle orother suitable injection device.

Referring now to FIG. 3 , an alternative embodiment of an artificialmuscle 100′ is illustrated. It should be appreciated that the artificialmuscle 100′ is similar to the artificial muscle 100 described herein. Assuch, like structure is indicated with like reference numerals. Thefirst electrode 106 and the second electrode 108 of the artificialmuscle 100′ have a circular geometry as opposed to the ellipsoidgeometry of the first electrode 106 and the second electrode 108 of theartificial muscle 100 described herein. As shown in FIG. 3 , withrespect to the second electrode 108, a first side edge length of thefirst side edge 154 a is equal to a second side edge length of thesecond side edge 154 b. Accordingly, the channels 155 formed betweenopposing side edges 154 a, 154 b of the fan portions 154 each have anequal length. Although the first electrode 106 is hidden from view inFIG. 3 by the second electrode 108, it should be appreciated that thefirst electrode 106 also has a circular geometry corresponding to thegeometry of the second electrode 108.

Referring now to FIGS. 4 and 5 , the artificial muscle 100 is actuatablebetween a non-actuated state and an actuated state. In the non-actuatedstate, as shown in FIG. 4 , the first electrode 106 and the secondelectrode 108 are partially spaced apart from one another proximate thecentral openings 146, 168 thereof and the first end 134, 156 of the fanportions 132, 154. The second end 136, 158 of the fan portions 132, 154remain in position relative to one another due to the housing 102 beingsealed at the outer perimeter 138 of the first electrode 106 and theouter perimeter 160 of the second electrode 108. In the actuated state,as shown in FIG. 5 , the first electrode 106 and the second electrode108 are brought into contact with and oriented parallel to one anotherto force the dielectric fluid 198 into the expandable fluid region 196.This causes the dielectric fluid 198 to flow through the centralopenings 146, 168 of the first electrode 106 and the second electrode108 and inflate the expandable fluid region 196.

Referring now to FIG. 4 , the artificial muscle 100 is shown in thenon-actuated state. The electrode pair 104 is provided within theelectrode region 194 of the unsealed portion 192 of the housing 102. Thecentral opening 146 of the first electrode 106 and the central opening168 of the second electrode 108 are coaxially aligned within theexpandable fluid region 196. In the non-actuated state, the firstelectrode 106 and the second electrode 108 are non-parallel to oneanother. The first film layer 122 is sealed to the second film layer 124around the electrode pair 104. Thus, dielectric fluid 198 is providedbetween the first electrode 106 and the second electrode 108, therebyseparating the first end 134, 156 of the fan portions 132, 154 proximatethe expandable fluid region 196. Stated another way, a distance betweenthe first end 134 of the fan portion 132 of the first electrode 106 andthe first end 156 of the fan portion 154 of the second electrode 108 isgreater than a distance between the second end 136 of the fan portion132 of the first electrode 106 and the second end 158 of the fan portion154 of the second electrode 108. This results in the electrode pair 104zippering toward the expandable fluid region 196 when actuated. Moreparticularly, zippering of the electrode pair 104 is initiated at thecorners 132 c of the first electrode 106 and the corners 154 c of thesecond electrode 108, as discussed herein. In some embodiments, thefirst electrode 106 and the second electrode 108 may be flexible. Thus,as shown in FIG. 4 , the first electrode 106 and the second electrode108 are convex such that the second ends 136, 158 of the fan portions132, 154 thereof may remain close to one another, but spaced apart fromone another proximate the central openings 146, 168. In the non-actuatedstate, the expandable fluid region 196 has a first height H1.

In embodiments, the artificial muscle 100 includes one or more clampingdevices 200 for compressing outer perimeters 138, 160 of the firstelectrode 106 and the second electrode 108 toward one another.Specifically, the one or more clamping devices 200 compress the firstelectrode 106 and the second electrode 108 to reduce the distancebetween the second end 136 of the fan portion 132 and the second end 158of the fan portion 154. Particularly, the compression by the clampingdevice 200 causes the first electrical insulator layer 110 and thesecond insulator layer 112 to contact one another proximate the outerperimeters 138, 160 of the first electrode 106 and the second electrode108. It should be appreciated that by compressing the first electrode106 and the second electrode 108 at the outer perimeters 138, 160, thevoltage required to actuate the artificial muscle 100 is reduced ascompared to a situation in which a gap or space is provided between thefirst electrical insulator layer 110 and the second electrical insulatorlayer 112 at the outer perimeters 138, 160.

As shown in FIG. 4 , a pair of clamping devices 200 are shown providedon opposite sides of the artificial muscle 100. However, it should beappreciated that more than two clamping devices 200 may be providedalong an outer perimeter of the artificial muscle 100. Each clampingdevice 200 includes an upper arm 202, an opposite lower arm 204, and abody 206 interconnecting the upper arm 202 and the lower arm 204. Theupper arm 202 has an inner surface 208 and an opposite outer surface210, the lower arm 204 has an inner surface 212 and an opposite outersurface 214, and the body 206 has an inner surface 216 and an oppositeouter surface 218. The inner surface 208 of the upper arm 202, the innersurface 212 of the lower arm 204, and the inner surface 216 of the body206 cooperate to define a cavity 220 configured to receive the housing102 and a portion of the first electrode 106 and the second electrode108.

The body 206 of the inner surface 216 of the body 206 of the clampingdevice 200 has a body distance Db defined between the upper arm 202 andthe lower arm 204. In embodiments, the body distance Db is less than 6mm. In embodiments, the body distance Db is between 1 mm and 6 mm. Inembodiments, the body distance Db is between 2 mm and 5 mm. Inembodiments, the body distance Db is between 3 mm and 4 mm. The clampingdevice 200 may be formed from any suitable material such as, forexample, metal, plastic, and the like. In embodiments, the inner surface208 of the upper arm 202 and the inner surface 212 of the lower arm 204are provided with an adhesive layer 222, 224 to secure the clampingdevice 200 onto the housing 102.

In embodiments, the clamping device 200 may be formed from a flexiblematerial providing a biasing force. Particularly, as shown in FIG. 4 ,the body distance Db appears to be less than a distance between a distalend 226 of the upper arm 202 and a distal end 228 of the lower arm 204opposite the body 206. This is due to the clamping device 200 beingformed from a flexible material allowing the upper arm 202 and the lowerarm 204 to be expanded away from one another when the artificial muscle100 is in the non-actuated state, yet provide a biasing force againstthe first electrode 106 and the second electrode 108. When theartificial muscle 100 is in the actuated state, as shown in FIG. 5 , thebiasing force of the clamping device 200 allows the upper arm 202 andthe lower arm 204 to flex toward one another. However, it should beappreciated that the clamping device 200 may be formed from a ridgedmaterial such that the body distance Db remains equal to a distancebetween the distal end 226 of the upper arm 202 and the distal end 228of the lower arm 204 opposite the body 206 such that the upper arm 202and the lower arm 204 are not permitted to flex away from one another,as shown in FIG. 5 .

As shown in FIG. 4 , the clamping device 200 is positioned relative tothe housing 102 such that the lower arm 204 and the upper arm 202partially extend to overlap the first electrode 106 and the secondelectrode 108, respectively, in a vertical direction extending parallelto the center axis C. In embodiments, the lower arm 204 extends alongthe first electrode 106 by a first length L1. In embodiments, the firstlength L1 is less than 50% of a first electrode length LE1 defined by adistance between the first end 134 and the second end 136 of the firstelectrode 106. In embodiments, the first length L1 is less than 40% ofthe first electrode length LE1. In embodiments, the first length L1 isless than 30% of the first electrode length LE1. In embodiments, thefirst length L1 is between 10% and 30% of the first electrode lengthLE1. Similarly, the upper arm 202 extends along the second electrode 108by a second length L2. In embodiments, the first length L1 may be thesame as the second length L2. In embodiments, the second length L2 isless than 50% of a second electrode length LE2 defined by a distancebetween the first end 156 and the second end 158 of the second electrode108. In embodiments, the second length L2 is less than 40% of the secondelectrode length LE2. In embodiments, the second length L2 is less than30% of the second electrode length LE2. In embodiments, the secondlength L2 is between 10% and 30% of the second electrode length LE2.

When actuated, as shown in FIG. 5 , the clamping device 200 provides aforce against the first electrode 106 and the second electrode 108causing the first electrode 106 and the second electrode 108 to zippertoward one another from the second ends 136, 158 of the fan portions132, 154 thereof, thereby pushing the dielectric fluid 198 into theexpandable fluid region 196. As shown, when in the actuated state, thefirst electrode 106 and the second electrode 108 are parallel to oneanother. In the actuated state, the dielectric fluid 198 flows into theexpandable fluid region 196 to inflate the expandable fluid region 196.As such, the first film layer 122 and the second film layer 124 expandin opposite directions. In the actuated state, the expandable fluidregion 196 has a second height H2, which is greater than the firstheight H1 of the expandable fluid region 196 when in the non-actuatedstate. Although not shown, it should be noted that the electrode pair104 may be partially actuated to a position between the non-actuatedstate and the actuated state. This would allow for partial inflation ofthe expandable fluid region 196 and adjustments when necessary.

In order to move the first electrode 106 and the second electrode 108toward one another, a voltage is applied by a power supply. In someembodiments, a voltage of up to 10 kV may be provided from the powersupply to induce an electric field through the dielectric fluid 198. Theresulting attraction between the first electrode 106 and the secondelectrode 108 pushes the dielectric fluid 198 into the expandable fluidregion 196. Pressure from the dielectric fluid 198 within the expandablefluid region 196 causes the first film layer 122 and the firstelectrical insulator layer 110 to deform in a first axial directionalong the center axis C of the first electrode 106 and causes the secondfilm layer 124 and the second electrical insulator layer 112 to deformin an opposite second axial direction along the center axis C of thesecond electrode 108. Once the voltage being supplied to the firstelectrode 106 and the second electrode 108 is discontinued, the firstelectrode 106 and the second electrode 108 return to their initial,non-parallel position in the non-actuated state.

It should be appreciated that the present embodiments disclosed herein,specifically, the fan portions 132, 154 with the interconnecting bridgeportions 140, 162, provide a number of improvements over actuators, suchas HASEL actuators, that do not include the fan portions 132, 154.Embodiments of the artificial muscle 100 including fan portions 132, 154on each of the first electrode 106 and the second electrode 108,respectively, increases the surface area and, thus, displacement at theexpandable fluid region 196 without increasing the amount of voltagerequired as compared to known HASEL actuators including donut-shapedelectrodes having a uniform, radially-extending width. In addition, thecorners 132 c, 154 c of the fan portions 132, 154 of the artificialmuscle 100 provide zipping fronts that result in focused and directedzipping along the outer perimeters 138, 160 of the first electrode 106and the second electrode 108 during actuation as compared to HASELactuators including donut-shaped electrodes. Specifically, one pair offan portions 132, 154 provides at least twice the amount of actuatorpower per unit volume as compared to donut-shaped HASEL actuators, whiletwo pairs of fan portions 132, 154 provide at least four times theamount of actuator power per unit volume. The bridge portions 140, 162interconnecting the fan portions 132, 154 also limit buckling of the fanportions 132, 154 by maintaining the distance between the channels 133,155 and the central openings 146, 168. Because the bridge portions 140,162 are integrally formed with the fan portions 132, 154, the bridgeportions 140, 162 also prevent tearing and leakage between the fanportions 132, 154 by eliminating attachment locations that provide anincreased risk of rupturing.

In operation, when the artificial muscle 100 is actuated, expansion ofthe expandable fluid region 196 produces a force of 20Newton-millimeters (N.mm) per cubic centimeter (cm³) of actuator volumeor greater, such as 25 N.mm per cm³ or greater, 30 N.mm per cm³ orgreater, 35 N.mm per cm³ or greater, 40 N.mm per cm³ or greater, or thelike. In one example, when the artificial muscle 100 is actuated by avoltage of 9.5 kilovolts (kV), the artificial muscle 100 provides aresulting force of 20 N.

Moreover, the size of the first electrode 106 and the second electrode108 is proportional to the amount of displacement of the dielectricfluid 198. Therefore, when greater displacement within the expandablefluid region 196 is desired, the size of the electrode pair 104 isincreased relative to the size of the expandable fluid region 196. Itshould be appreciated that the size of the expandable fluid region 196is defined by the central openings 146, 168 in the first electrode 106and the second electrode 108. Thus, the degree of displacement withinthe expandable fluid region 196 may alternatively, or in addition, becontrolled by increasing or reducing the size of the central openings146, 168.

As shown in FIGS. 6 and 7 , another embodiment of an artificial muscle100″ including the pair of clamping devices 200 is illustrated. Theartificial muscle 100″ is substantially similar to the artificial muscle100. As such, like structure is indicated with like reference numerals.However, as shown, the first electrode 106 does not include a centralopening, such as the central opening 146. Thus, only the secondelectrode 108 includes the central opening 168 formed therein. As shownin FIG. 6 , the artificial muscle 100″ is in the non-actuated state withthe first electrode 106 being planar and the second electrode 108 beingconvex relative to the first electrode 106. In the non-actuated state,the expandable fluid region 196 has a first height H3. In the actuatedstate, as shown in FIG. 7 , the expandable fluid region 196 has a secondheight H4, which is greater than the first height H3. It should beappreciated that by providing the central opening 168 only in the secondelectrode 108 as opposed to both the first electrode 106 and the secondelectrode 108, the total deformation may be formed on one side of theartificial muscle 100″. In addition, because the total deformation isformed on only one side of the artificial muscle 100″, the second heightH4 of the expandable fluid region 196 of the artificial muscle 100″extends further from a longitudinal axis perpendicular to the centeraxis C of the artificial muscle 100″ than the second height H2 of theexpandable fluid region 196 of the artificial muscle 100 when all otherdimensions, orientations, and volume of dielectric fluid are the same.

Referring to FIG. 8 , the clamping device 200 is shown apart from theartificial muscles 100, 100″. Referring now to FIG. 9 , a partial viewof another clamping device 300 is shown. Although only a portion of theclamping device 300 is shown, it should be appreciated that the clampingdevice 300 is substantially a ring-shaped member to completely encirclean artificial muscle. As such, only a single clamping device 300 isutilized as opposed to a plurality of individual clamping devices 200.Similar to the clamping device 200, the clamping device 300 includeslike structure such as, an upper arm 302, an opposite lower arm 304, anda body 306 extending between the upper arm 302 and the lower arm 304.The upper arm 302, the lower arm 304, and the body 306 cooperate todefine a cavity 308 to receive the housing 102 of the artificial muscle100. As the clamping device 300 is a ring-shaped member, an innersurface 310 of the body 306 defines a curvature corresponding to theouter perimeter of an artificial muscle, particularly the firstelectrode 106 and the second electrode 108. Similarly, in embodiments,the upper arm 302 has a distal end 312 and the lower arm 304 has adistal end 314 also defining a ring shape corresponding to the innersurface 310 of the body 306.

Referring now to FIG. 10 , another embodiment of a clamping device 300′is shown. The clamping device 300′ includes an upper arm 350, a lowerarm 352, at least one intermediate arm 354, and a body 356interconnecting the upper arm 350, the lower arm 352, and the at leastone intermediate arm 354. As shown, the clamping device 300′ includes aplurality of intermediate arms 354 arranged between the upper arm 350and the lower arm 352. As such, the clamping device 300′ is similar tothe clamping device 200 with the addition of the one or moreintermediate arms 354, thereby defining a plurality of cavities 358. Itshould be appreciated that the clamping device 300′ is particularlyuseful when providing a clamping force on an electrode pair of aplurality of artificial muscles, as illustrated in FIG. 11 , such thateach cavity 358 is configured to receive a corresponding housing of anartificial muscle stack. It should be appreciated that the featuresdiscussed herein with regard to the clamping devices 200, 300, 300′ areinterchangeable and not specific to any one embodiment.

Referring now to FIG. 11 , an artificial muscle assembly 380 is shownincluding a plurality of artificial muscles, such the artificial muscle100, and a plurality of clamps 300′. However, it should be appreciatedthat a plurality of artificial muscles 100′ or artificial muscles 100″may similarly be arranged in a stacked formation. Each artificial muscle100 may be identical in structure and arranged in a stack such that theexpandable fluid region 196 of each artificial muscle 100 overlies theexpandable fluid region 196 of an adjacent artificial muscle 100. Theterminals 130, 152 of each artificial muscle 100 are electricallyconnected to one another such that the artificial muscles 100 may besimultaneously actuated between the non-actuated state and the actuatedstate. By arranging the artificial muscles 100 in a stackedconfiguration, the total deformation of the artificial muscle assembly380 is the sum of the deformation within the expandable fluid region 196of each artificial muscle 100. As such, the resulting degree ofdeformation from the artificial muscle assembly 380 is greater than thatwhich would be provided by the artificial muscle 100 alone.

Referring now to FIG. 12 , an actuation system 400 may be provided foroperating an artificial muscle or an artificial muscle assembly, such asthe artificial muscles 100, 100′, 100″ or the artificial muscle assembly380 between the non-actuated state and the actuated state. Thus, theactuation system 400 may include a controller 402, an operating device404, a power supply 406, and a communication path 408. The variouscomponents of the actuation system 400 will now be described.

The controller 402 includes a processor 410 and a non-transitoryelectronic memory 412 to which various components are communicativelycoupled. In some embodiments, the processor 410 and the non-transitoryelectronic memory 412 and/or the other components are included within asingle device. In other embodiments, the processor 410 and thenon-transitory electronic memory 412 and/or the other components may bedistributed among multiple devices that are communicatively coupled. Thecontroller 402 includes non-transitory electronic memory 412 that storesa set of machine-readable instructions. The processor 410 executes themachine-readable instructions stored in the non-transitory electronicmemory 412. The non-transitory electronic memory 412 may comprise RAM,ROM, flash memories, hard drives, or any device capable of storingmachine-readable instructions such that the machine-readableinstructions can be accessed by the processor 410. Accordingly, theactuation system 400 described herein may be implemented in anyconventional computer programming language, as pre-programmed hardwareelements, or as a combination of hardware and software components. Thenon-transitory electronic memory 412 may be implemented as one memorymodule or a plurality of memory modules.

In some embodiments, the non-transitory electronic memory 412 includesinstructions for executing the functions of the actuation system 400.The instructions may include instructions for operating the artificialmuscles 100, 100′, 100″ or the artificial muscle assembly 380 based on auser command.

The processor 410 may be any device capable of executingmachine-readable instructions. For example, the processor 410 may be anintegrated circuit, a microchip, a computer, or any other computingdevice. The non-transitory electronic memory 412 and the processor 410are coupled to the communication path 408 that provides signalinterconnectivity between various components and/or modules of theactuation system 400. Accordingly, the communication path 408 maycommunicatively couple any number of processors with one another, andallow the modules coupled to the communication path 408 to operate in adistributed computing environment. Specifically, each of the modules mayoperate as a node that may send and/or receive data. As used herein, theterm “communicatively coupled” means that coupled components are capableof exchanging data signals with one another such as, for example,electrical signals via conductive medium, electromagnetic signals viaair, optical signals via optical waveguides, and the like.

As schematically depicted in FIG. 12 , the communication path 408communicatively couples the processor 410 and the non-transitoryelectronic memory 412 of the controller 402 with a plurality of othercomponents of the actuation system 400. For example, the actuationsystem 400 depicted in FIG. 12 includes the processor 410 and thenon-transitory electronic memory 412 communicatively coupled with theoperating device 404 and the power supply 406.

The operating device 404 allows for a user to control operation of theartificial muscles 100, 100′, 100″ or the artificial muscle assembly380. In some embodiments, the operating device 404 may be a switch,toggle, button, or any combination of controls to provide useroperation. As a non-limiting example, a user may actuate the artificialmuscles 100, 100′, 100″ or the artificial muscle assembly 380 into theactuated state by activating controls of the operating device 404 to afirst position. While in the first position, the artificial muscles 100,100′, 100″ or the artificial muscle assembly 380 will remain in theactuated state. The user may switch the artificial muscles 100, 100′,100″ or the artificial muscle assembly 380 into the non-actuated stateby operating the controls of the operating device 404 out of the firstposition and into a second position.

The operating device 404 is coupled to the communication path 408 suchthat the communication path 408 communicatively couples the operatingdevice 404 to other modules of the actuation system 400. The operatingdevice 404 may provide a user interface for receiving user instructionsas to a specific operating configuration of the artificial muscles 100,100′, 100″ or the artificial muscle assembly 380. In addition, userinstructions may include instructions to operate the artificial muscles100, 100′, 100″ or the artificial muscle assembly 380 only at certainconditions.

The power supply 406 (e.g., battery) provides power to the artificialmuscles 100, 100′, 100″ or the artificial muscle assembly 380. In someembodiments, the power supply 406 is a rechargeable direct current powersource. It is to be understood that the power supply 406 may be a singlepower supply or battery for providing power to the artificial muscle100, 100′, 100″ or the artificial muscle assembly 380. A power adapter(not shown) may be provided and electrically coupled via a wiringharness or the like for providing power to the artificial muscles 100,100′, 100″ or the artificial muscle assembly 380 via the power supply406.

In some embodiments, the actuation system 400 also includes a displaydevice 414. The display device 414 is coupled to the communication path408 such that the communication path 408 communicatively couples thedisplay device 414 to other modules of the actuation system 400. Thedisplay device 414 may output a notification in response to an actuationstate of the artificial muscles 100, 100′, 100″ or the artificial muscleassembly 380 or indication of a change in the actuation state of theartificial muscles 100, 100′, 100″ or the artificial muscle assembly380. Moreover, the display device 414 may be a touchscreen that, inaddition to providing optical information, detects the presence andlocation of a tactile input upon a surface of or adjacent to the displaydevice 414. Accordingly, the display device 414 may include theoperating device 404 and receive mechanical input directly upon theoptical output provided by the display device 414.

In some embodiments, the actuation system 400 includes network interfacehardware 416 for communicatively coupling the actuation system 400 to aportable device 418 via a network 420. The portable device 418 mayinclude, without limitation, a smartphone, a tablet, a personal mediaplayer, or any other electric device that includes wirelesscommunication functionality. It is to be appreciated that, whenprovided, the portable device 418 may serve to provide user commands tothe controller 402, instead of the operating device 404. As such, a usermay be able to control or set a program for controlling the artificialmuscles 100, 100′, 100″ or the artificial muscle assembly 380 withoututilizing the controls of the operating device 404. Thus, the artificialmuscles 100, 100′, 100″ or the artificial muscle assembly 380 may becontrolled remotely via the portable device 418 wirelessly communicatingwith the controller 402 via the network 420.

From the above, it is to be appreciated that defined herein areartificial muscles for inflating or deforming a surface of an object byselectively actuating the artificial muscle to raise and lower a regionthereof. This provides a low profile inflation member that may operateon demand.

It is noted that the terms “substantially” and “about” may be utilizedherein to represent the inherent degree of uncertainty that may beattributed to any quantitative comparison, value, measurement, or otherrepresentation. These terms are also utilized herein to represent thedegree by which a quantitative representation may vary from a statedreference without resulting in a change in the basic function of thesubject matter at issue.

While particular embodiments have been illustrated and described herein,it should be understood that various other changes and modifications maybe made without departing from the scope of the claimed subject matter.Moreover, although various aspects of the claimed subject matter havebeen described herein, such aspects need not be utilized in combination.It is therefore intended that the appended claims cover all such changesand modifications that are within the scope of the claimed subjectmatter.

1. An artificial muscle comprising: a housing comprising an electroderegion and an expandable fluid region; an electrode pair positioned inthe electrode region of the housing, the electrode pair comprising afirst electrode positioned adjacent a first surface of the housing and asecond electrode positioned adjacent a second surface of the housing,the first electrode and the second electrode each having a first endproximate the expandable fluid region and a second end opposite theexpandable fluid region; a dielectric fluid housed within the housing;and a clamping device applying a force against the first electrode andthe second electrode at opposite sides of the second end of the firstelectrode and the second electrode, wherein the electrode pair isactuatable between a non-actuated state and an actuated state such thatactuation from the non-actuated state to the actuated state directs thedielectric fluid into the expandable fluid region.
 2. The artificialmuscle of claim 1, wherein the clamping device comprises: an upper armhaving an inner surface and an opposite outer surface; a lower armhaving an inner surface and an opposite outer surface; and a body havingan inner surface and an opposite outer surface, the body interconnectingthe upper arm and the lower arm; wherein the inner surface of the upperarm, the inner surface of the lower arm, and the inner surface of thebody cooperate to define a cavity, the housing partially received withinthe cavity.
 3. The artificial muscle of claim 2, wherein the innersurface of the body of the clamping device has a body distance definedbetween the upper arm and the lower arm, the body distance is less than6 mm.
 4. The artificial muscle of claim 3, wherein the body distance isbetween 3 mm and 4 mm.
 5. The artificial muscle of claim 2, wherein: thelower arm extends along the first electrode by a first length, the firstlength is less than 50% of a first electrode length defined by adistance between the first end of the first electrode and the second endof the first electrode; and the upper arm extends along the secondelectrode by a second length, the second length is less than 50% of asecond electrode length defined by a distance between the first end ofthe second electrode and the second end of the second electrode.
 6. Theartificial muscle of claim 2, wherein the clamping device is aring-shaped member.
 7. The artificial muscle of claim 1, wherein: thefirst electrode and the second electrode each comprise two or more fanportions and two or more bridge portions; each of the two or more bridgeportions interconnects adjacent fan portions; and at least one of thefirst electrode and the second electrode comprises a central openingpositioned between the two or more fan portions and encircling theexpandable fluid region.
 8. The artificial muscle of claim 7, furthercomprising a plurality of clamping devices, each clamping device of theplurality of clamping devices positioned at a corresponding one of twoor more fan portions of the first electrode and the second electrode. 9.The artificial muscle of claim 2, wherein the clamping device comprisesan intermediate arm extending from the body, the clamping devicedefining a first cavity between the upper arm and the intermediate arm,and a second cavity between the lower arm and the intermediate arm. 10.The artificial muscle of claim 1, further comprising a first electricalinsulator layer fixed to an inner surface of the first electrodeopposite the first surface of the housing and a second electricalinsulator layer fixed to an inner surface of the second electrodeopposite the second surface of the housing, wherein the first electricalinsulator layer and the second electrical insulator layer each includesan adhesive surface and an opposite non-sealable surface.
 11. Theartificial muscle of claim 10, wherein the clamping device compressesthe housing such that the first electrical insulator layer and thesecond electrical insulator layer contact proximate the second end ofthe first electrode and the second electrode.
 12. An artificial musclecomprising: a housing comprising an electrode region and an expandablefluid region; an electrode pair positioned in the electrode region ofthe housing, the electrode pair comprising a first electrode fixed to afirst surface of the housing and a second electrode fixed to a secondsurface of the housing, at least one of the first electrode and thesecond electrode comprising a central opening encircling the expandablefluid region, the first electrode and the second electrode each having afirst end proximate the expandable fluid region and a second endopposite the expandable fluid region; a dielectric fluid housed withinthe housing; and a clamping device applying a force against the firstelectrode and the second electrode at opposite sides of the second endof the first electrode and the second electrode to reduce a gap betweenthe second end of the first electrode and the second end of the secondelectrode, wherein the electrode pair is actuatable between anon-actuated state and an actuated state such that actuation from thenon-actuated state to the actuated state directs the dielectric fluidinto the expandable fluid region.
 13. The artificial muscle of claim 12,wherein the clamping device comprises: an upper arm having an innersurface and an opposite outer surface; a lower arm having an innersurface and an opposite outer surface; and a body having an innersurface and an opposite outer surface, the body interconnecting theupper arm and the lower arm; wherein the inner surface of the upper arm,the inner surface of the lower arm, and the inner surface of the bodycooperate to define a cavity, the housing partially received within thecavity.
 14. The artificial muscle of claim 13, wherein the inner surfaceof the body of the clamping device has a body distance defined betweenthe upper arm and the lower arm, the body distance is less than 6 mm.15. The artificial muscle of claim 13, wherein: the lower arm extendsalong the first electrode by a first length L1, the first length L1 isless than 50% of a first electrode length defined by a distance betweenthe first end of the first electrode and the second end of the firstelectrode; and the upper arm extends along the second electrode by asecond length, the second length is less than 50% of a second electrodelength defined by a distance between the first end of the secondelectrode and the second end of the second electrode.
 16. The artificialmuscle of claim 13, wherein the clamping device is a ring-shaped member.17. The artificial muscle of claim 13, wherein the clamping devicecomprises an intermediate arm extending from the body, the clampingdevice defining a first cavity between the upper arm and theintermediate arm, and a second cavity between the lower arm and theintermediate arm.
 18. A method for actuating an artificial muscleassembly, the method comprising: generating a voltage using a powersupply electrically coupled to an electrode pair of an artificialmuscle, the artificial muscle comprising: a housing with an electroderegion and an expandable fluid region, the electrode pair is positionedin the electrode region of the housing, the electrode pair comprising afirst electrode positioned adjacent a first surface of the housing and asecond electrode positioned adjacent a second surface of the housing,the first electrode and the second electrode each having a first endproximate the expandable fluid region and a second end opposite theexpandable fluid region; a clamping device applying a force against thefirst electrode and the second electrode at opposite sides of the secondend of the first electrode and the second electrode; and a dielectricfluid housed within the housing, and applying the voltage to theelectrode pair of the artificial muscle, thereby actuating the electrodepair from a non-actuated state and an actuated state such that thedielectric fluid is directed into the expandable fluid region of thehousing and expands the expandable fluid region.
 19. The method of claim18, wherein the clamping device comprises: an upper arm having an innersurface and an opposite outer surface; a lower arm having an innersurface and an opposite outer surface; and a body having an innersurface and an opposite outer surface, the body interconnecting theupper arm and the lower arm; wherein the inner surface of the upper arm,the inner surface of the lower arm, and the inner surface of the bodycooperate to define a cavity, the housing partially received within thecavity.
 20. The method of claim 19, wherein: the lower arm extends alongthe first electrode by a first length, the first length is less than 50%of a first electrode length defined by a distance between the first endof the first electrode and the second end of the first electrode; andthe upper arm extends along the second electrode by a second length, thesecond length is less than 50% of a second electrode length defined by adistance between the first end of the second electrode and the secondend of the second electrode.